Combined directional control and priority valve



Q. L. RICE Jan. 18, 1966 COMBINED DIRECTIONAL CONTROL AND PRIORITY VALVE 2, Sheets-Sheet 1 Filed March 21, 1963 NOE INVENTOR.

ORVAL L. RICE ATTOR NEYS Jan. 18, 1966 o. RICE 3,229,717

COMBINED DIRECTIONAL CONTROL AND PRIORITY VALVE INVENTOR ORVAL L. RICE ATTORNEYS IQQ Unite taes Patent Office 3,229,717 Patented Jan. 18, 1966 3,229,717 COMBINED DIRECTIONAL CONTROL AND PRIORITY VALVE Orval L. Rice, Kalamazoo, Mich., assignor to The New York Air Brake Company, a corporation of New Jersey Filed Mar. 21, 1963, Ser. No. 267,392 8 Claims. (Cl. 137596.12)

This application is a continuation-in-part of my copending application Serial No. 246,076, filed December 20, 1962, now abandoned.

This invention relates to hydraulic valves, and more particularly to directional control valves of the sliding plunger type.

In a known valve of this type, the housing contains one or more through parallel valve bores for receiving sliding valve plungers, and a generally C-shaped exhaust manifold that has a body portion which is parallel with the bores and two leg portions which extend in directions transverse to the bores and which intersect each bore adjacent its opposite ends. The valve plungers are connected in a series supply path and the bore associated with the last plunger in the series is separated from the exhaust manifold by an internal housing wall containing a first passage which constitutes the terminal portion of the supply path. Directly across the exhaust manifold from the first passage is a second pas-sage which leads through the outside surface of the valve housing.

When this type of valve is used by itself, the second passage is connected directly with a reservoir so that the supply path is unloaded through this passage and the exhaust manifold. In those cases where the valve is connected in a series circuit with another valve, the exhaust manifold is bridged by a sleeve which is received in the first and second passages and is connected with a reservoir through another port. Here the supply path is loaded and unloaded by the downstream valve. In these last mentioned installations it sometimes happens that the loads controlled by the second or downstream valve require smaller flow rates than those controlled by the upstream valve. In these instances, the conduit connecting the second passage of the upstream valve with the inlet port of the downstream valve is provided with a priority valve that passes a predetermined rate of flow and bypasses the excess flow to the reservoir. This arrangement, while satisfactory from a function-a1 standpoint, is inconvenient because it requires that the conduit between the two valves be broken to insert the priority valve and also that a separate by-pass conduit be provided in order to connect the priority valve with the reservoir. In spite of the fact that this arrangement has been used rather frequently for a considerable number of years, the art, as far as I am aware, has not proposed a more compact and convenient arrangement.

The object of this invention is to provide a combination control and priority valve which performs the function of the known circuit just mentioned but which is con siderably simpler to use. According to this invention, the body portion of the exhaust manifold is bridged by a priority valve unit that is received in the first and second passages and which responds to the rate of flow through these passages. When the rate of flow is below a predetermined rate deemed adequate to supply the demands imposed by the loads controlled by the downstream control valve, the priority valve transmits to the second passage all of the fluid flowing into it through the first passage. However, as the flow rate rises above this value, the priority valve progressively opens a flow path between the first passage and the exhaust manifold and thus diverts the excess fluid. With this arrangement, the conduit connecting the two control valves need not be broken and no separate bypass conduit need be provided because the exhaust manifold forms part of the by-pass path and it is already connected with the reservoir. Therefore, this scheme is more compact and convenient than the one which has characterized this art for years.

The preferred embodiments of the invention are described herein in detail with reference to the accompanying drawings in which:

FIG. 1 is a sectional view of a combination control and priority valve using one form of priority valve unit.

FIG. 2 is a sectional view taken on line 22 of FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view showing an alternative form of priority valve which can be used in control valve housings similar to the one shown in FIG. 1.

FIG. 4 is a sectional view of a portion of another combination control and priority valve.

As shown in FIG. 1, the directional control valve comprises a housing 11 containing a through valve bore 12 which is encircled by seven annular chambers 1349, and which receives a three-position sliding valve plunger 21 of the single-acting type. Annular chambers 15 and 17 are connected with an inlet port 22 through a branched supply passage 23, chamber 14 is connected with a motor port (not shown), chamber 18 is blind, and chambers 13 and 19 are connected with the transverse legs 24 and 24 of a generally C-shaped exhaust manifold 25. A pilotoperated relief valve 26 is interposed in the housing between supply passage 23 and the legs 24 and 24' of the exhaust manifold.

Valve plunger 21 is provided with two annular grooves 27 and 28 that define three lands 29, 31 and 32. Within land 29 is an axial bore (not shown) which communicates with two spaced sets of radial passages 33 and 34 and which contains a check valve (not shown) arranged to prevent flow through the axial bore from passages 33 to passages 34. When plunger 21 is in the illustrated neutral position, land 29 isolates annular chamber 14 from annular chambers 13 and 15 and, therefore, the single-acting motor (not shown) connected with this chamber is hydraulically locked. Valve plunger 21 has two other operative positions, namely, a supply position, located to the right of the neutral position, in which passages 33 and 34 register with annular chambers 14 and 15, respectively, and land-s 29 and 31 isolate chamber 16 from chambers 15 and 17, and an exhaust position, located to the left of the neutral position, in which passages 33 and 34 register with annular chambers 13 and 14, respectively, and lands 31 and 32 isolate annular chamber 16 from annular chambers 15 and 17. Valve plunger 21 is of the known hollow plunger design so further description is deemed unnecessary.

The exhaust manifold 25 has a body portion 35 wh ch is parallel with and spaced from valve bore 12 and which is provided with an exhaust port 36. Opening into body portion 35 are two aligned bores 37 and 38, the bore 37 leading to annular chamber 16 and the bore 38 leading to a carry-over port 39. These bores 37 and 38 receive the opposite ends of a carry-over sleeve 41 that bridges body portion 35 and which is seated against a shoulder formed in bore 37. Sleeve 41 is held in place by a snap ring 42 and contains two longitudinally spaced sets of radial by-pass passages 43 and 44 that open into the exhaust manifold. Reciprocable in sleeve 41 is a bypass valve 45 which is arranged to open and close the by-pass passages. Valve 45 is formed with an axial bore 46 containing a metering orifice 47 and is biased to the closed position, defined by snap ring 48, by a coil compression spring 49. The pressures upstream and downstream of orifice 47 act on opposite ends of valve 45, and since the differential between these pressures is proportional to the rate of flow through the orifice, it will be apparent that valve 45 is positioned in accordance with this flow rate.

In operation, inlet port 22 is connected with a pump, exhaust port 36 is connected with a reservoir, the motor port (not shown) communicating with annular chamber 14 is connected with a single-acting piston motor, and carry-over port 39 is connected with the inlet port of a second valve, which may be identical to the one described herein. When the plunger 21 is in the supply position, the fluid delivered to inlet port 22 by the pump is transmitted to the single-acting motor via passage 23, annular chamber 15, radial passages 34, the axial bore in plunger 21, radial passages 33 and annular chamber 14. On the other hand, when plunger 21 is moved to the exhaust position, fluid is exhausted from the single-acting motor along a path which comprises annular chamber 14, radial passages 34, the axial bore in plunger 21, radial passages 33, annular chamber 13, manifold leg 24, manifold body portion 35 and exhaust port 36. In both of these positions of plunger 21, chamber 16 is isolated from chambers and 17 so the pump is loaded.

When valve plunger 21 is in the illustrated neutral position, and the single-acting motor controlled by it is not being operated, a portion of the fluid entering inlet port 22 is delivered to carry-over port 39 along a path which comprises passage 23, annular chambers 15 and 17, plunger grooves 27 and 28, annular chamber 16, bore 37, orifice 47, axial bore 46, bore 38 and carry-over port 39. If the second control valve connected with this port 39 is in a position to operate the associated motor or motors, the supply pump will be loaded, and if it is in a neutral position the pump will be unloaded. In any event, the quantity of fluid flowing to this second valve is determined by metering orifice 47. As the flow rate through the orifice increases toward the predetermined value deemed adequate for the demands imposed by the motor or motors controlled by the second control valve, the pressure drop across the orifice increases and valve 45 is moved toward open position against the bias of spring 49. When the flow rate exceeds that predetermined value, valve 45 uncovers passages 43 and permits the excess fluid to flow into the exhaust manifold and thence to tank through exhaust port 36. In those cases where the rate of delivery of the supply pump is considerably higher than the predetermined value, valve 45 moves far enough to uncover passages 44 so that fluid is by-passed to tank through both sets of by-pass passages.

From this discussion, it will be apparent that valve 45 will graduate the flow through the by-pass passages in accordance 'with the flow rate so that a substantially constant rate of flow will be delivered to the carry-over port 39. It also will be apparent that whenever plunger 21 is moved to either its supply or exhaust position, the flow of fluid to the by-pass valve will be interrupted and the pressures upstream and downstream of orifice 47 will equalize. At these times, spring 49 moves valve 45 to the closed position.

While the illustrated valveplunger 21 is of the singleacting, hollow plunger type and has three operative positions, it will be obvious that the type of valve plunger used is not an essential part of the invention. Other types of valve plungers, such as solid plungers, doubleacting plungers and plungers having more or fewer operative positions can be used. It also will be obvious that since plunger 21 is of the single-acting type, it is not necessary that it load the pump (i.e., isolated annular chamber 16 from annular chambers 15 and 17) when in the exhaust position. This loading action is present in the illustrated valve because the same housing 11 can be used with a double-acting plunger.

The form of by-pass or priority valve shown in FIG. 1 is useful in those cases where it is desired to incorporate the invention in an existing directional control valve design. In the case of new designs, provision can be made for the simpler, and thus less expensive, version of the by-pass valve illustrated in FIG. 3. As shown in this figure, the valve housing 11a is so formed that the bores 37a and 38a themselves are long enough to support and guide-the movable element of the by-pass valve. Therefore, in this case, the by-pass valve does not use a stationary sleeve analogous to sleeve 41 in FIG. 1, but requires only the reciprocable tubular valve member 45a. The opposite ends of valve 45a are guided in bores 37a and 38a, respectively, and the sliding fit between these members is sufliciently tight to provide the required seal between the bores and the body portion 35a of the exhaust manifold. Valve 45a is provided with a central partition which acts as a seat for the biasing spring 49a and in which is formed the metering orifice 47a. Upstream of the orifice 47a, the wall of the tubular valve 45a is pierced by a plurality of longitudinally offset bypass passages 44a. These passages are so positioned that when the valve member 45a is in the illustrated position, in which it abuts shoulder 48a, they are closed by the wall of bore 37a. As the by-pass valve 45a moves upward, as a result of an increase in the rate of flow through the metering orifice 47a, these passages 44a are brought into sequential registration with the body portion 35a of the exhaust manifold. While the FIG. 3 embodiment is much simpler than the FIG. 1 embodiment, functionally the two forms of the invention are exactly the same. Therefore, further description of operation is deemed unnecessary.

The housing 11 of FIG. 1 is a one-piece unit and its arrangement of passages and chambers is typical of those used in multi-unit valves employing the so-called seriesparallel circuit, i.e., a circuit which the supply paths leading to the plungers are connected in series and the exhaust paths leading from the plungers are connected in parallel. FIG. 4 illustrates the manner in which the invention may be incorporated in a directional control valve of the sectional type, employing a straight series circuit, i.e., a circuit in which the supply paths are connected in series and the exhaust flow lfI'OI'I]. each plunger is led to the succeeding plungers in the series and serves as their supply flow.

The valve illustrated in FIG. 4 includes a plurality of plunger sections 51, an exhaust section 52, and an inlet section (not shown) that contains an inlet port and a relief valve similar to those shown in the Lower part of the housing 11 in FIG. 1. These sections are held together in assembled relationship by bolts (not shown). All of the plunger sections 51 are identical and each includes a through valve bore 12b that is intersected by an annular supply chamber 15b, a pair of annular motor chambers 14b and 18b, a pair of exhaust chambers 16b and and a pair of transverse exhaust passages 13b and 19b. The valve bore contains a threeposition, hollow valve plunger 21b of the double-acting type formed with two grooves 27b and 28b which define three land 29b, 31b and 32b. The valve plunger contains two axial bores (not shown), one of which is intersected by radial passages 33b and 34b, and the other of which is intersected by radial passages 33 and 34c, respectively.

The exhaust section 52 is formed with a carry-over port 39b and an exhaust port 36b, and an exhaust manifold 25b having a body portion 35b parallel with the valve bore 12b and a pair of transverse leg portions 24b and 24b that form continuations of the transverse exhaust passages 13b and 19b, respectively. Opening into body portion 35b are a pair of aligned bores 37b and 38b which are connected with annular chambers 16b and 160 and carry-over port 39b, respectively, and which receive a tubular priority valve 45b. This priority valve is essentially the same as the one shown in FIG. 3 except that its lower end is provided with notches 53 which connect its interior with the chambers 16b and 16c.

It will be noticed that in the sectional valve design, the bore 37b that guides the priority valve is located wholly within the exhaust section 52. Valve 45b contains bypass passages 44b and a metering orifice 47b analogous to the parts 44a and 47a in FIG. 3, and is biased downward against the surface 48b in section 51 by a coil compression spring 49b.

Each of the plungers 21b of the valve shown in FIG. 4 controls a double-acting motor whose opposite sides are connected with chambers 14b and 18b, respectively. When the valve plungers 21b of the various sections 51 are in the illustrated neutral position, the fluid delivered to the valve by the pump passes through each section along a path including chamber 15b, plunger grooves 27b and 28b, and annular chambers 16b and 160. The fluid which leaves the chambers 16b and 160 of the last section in the series flows through the priority valve 45b to the carry-over port 39b. As in the previous embodiments, fluid in excess of that required by the downstream demands is diverted to the reservoir through by-pass passages 44b, body portion 35b and exhaust port 36b.

When a plunger 21b is shifted to the left from the neutral position to a second position, lands 31b and 32b interrupt communication between annular chamber 15b and chambers 16b and 16c, respectively, plunger groove 27b interconnects chambers 14b and 16b, and radial passages 34c and 330 and the axial bore with which they are connected interconnect annular chambers 15b and 18b. Fluid supplied by the pump is now delivered to that side of the double-acting motor that is connected with chamber 18b. The fluid displaced from the opposite side of the controlled motor is returned to chamber 14b and thence, through plunger groove 27b and annular chamber 16b, to the next plunger in the series. If plunger 21b is shifted to the right from the neutral position to its third position, lands 29b and 31b interrupt communication between chamber 15b and chambers 16b and 16c, respectively, plunger groove 28b interconnects chambers 16c and 18b, and radial passages 33b and 34b and the axial bore connecting them interconnect annular chambers 14b and 16b. Fluid now flows to the side of the controlled motor connected with chamber 14b and is exhausted from the side connected with chamber 18b.

It should be apparent from this discussion that whenever a plunger 21b is in its second or third position and the succeeding plungers 21b in the series are all in the neutral position, the exhaust flow returning from the first plunger passes through the other sections and, if its rate of flow is not above the setting of valve 45b, is delivered to the carry-over port 39b. Of course, if the rate of flow is above this value, excess fluid is diverted to the exhaust manifold. On the other hand, if one or more of the plungers 21b further down the series also is in an operative position, the exhaust flow from the first plunger becomes the supply flow for the next plunger and the exhaust flow from the second plunger is used either as the supply flow for another actuated plunger, if another is in an operative position, or is delivered to the carry-over port. In any of these cases, once the motor controlled by the first actuated plunger in the series reaches full stroke, the supply of fluid to the downstream plungers or to carry-over port 39b will be interrupted.

As stated previously, the drawings and description relate only to the preferred embodiments of the invention. Since many changes, some of which have been mentioned, can be made in the structures of these embodiments without departing from the inventive concept, the following claims should provide the sole measure of the scope of the invention.

What I claim is:

1. In a directional control valve of the type including a housing containing a through valve bore and a generally C-shaped exhaust chamber having a body portion .parallel with and spaced from the valve bore to define an intervening internal housing wall and two leg portions which extend in directions transverse to the Valve bore and intersect that bore adjacent its opposite ends, a first passage extending through said internal wall and connecting the valve bore with the body portion of the exhaust chamber, and a second passage extending into the housing from its outside surface and intersecting the body portion of the exhaust chamber in alignment with and across the chamber from the first passage, the improvement which comprises priority valve means extending across the body portion of the exhaust chamber and having opposite end portions that are received in said first and second passages, the priority valve means serving to transmit to the second passage all of the fluid flowing through the first passage when the rate of this flow is below a predetermined value and, when the rate of flow is above this value, to transmit fluid at said predetermined flow rate to the second passage and to divert the balance or said flow into the exhaust chamber.

2. The improvement defined in claim 1 in which the priority valve means comprises (a) a sleeve extending across the body portion of the exhaust chamber and having opposite end portions that are received in said first and second passages;

(b) means securing the sleeve in place in the housing;

(c) means sealing the outer periphery of the sleeve in the regions of said end portions;

(d) at least one by-pass port in the sleeve for connecting its interior with the body portion of the exhaust chamber;

(e) a by-pass valve slidable in and longitudinally of the sleeve between first and second positions in which, respectively, the by-pass port is closed and opened;

(f) spring means in the sleeve and urging the by-pass valve toward the closed position;

(g) a restricted metering passage within the sleeve establishing continuous communication between the first and second passages;

(h) first means carried by the by-pass valve and responsive to the pressure in the first passage for urging the by-pass valve toward the open position; and

(i) second means carried by the by-pass valve and responsive to the pressure in the second passage for urging the by-pass valve toward the closed position.

3. The improvement defined in claim 2 in which the second passage has a cross-section so shaped and sized that the sleeve may be inserted through it into position in the first passage.

4. The improvement defined in claim 3 in which the metering passage comprises (a) an axial passage extending through the by-pass valve; and

(b) a metering orifice positioned in the axial passage.

5. The improvement defined in claim 4 in which the first and second pressure response means are the opposite ends of the by-pass valve.

6. The improvement defined in claim 1 in which the priority valve means comprises (a) a reciprocable tubular valve member extending across the body portion of the exhaust chamber and having portions received in the first and second passages, respectively;

(b) a metering orifice positioned within the tubular valve member and arranged to restrict flow from the first to the second passage;

(c) at least one by-pass port located upstream of the metering orifice and extending through the wall of that portion of the tubular valve member received in the first passage,

(d) the valve member being shiftable between a first position in which the by-pass port is closed by the wall of said first passage and a second position in which the by-pass port registers with the body portion of the exhaust chamber; and

(e) a spring reacting between the housing and the 7 tubular valve member and urging that member toward its first position.

7. The improvement defined in claim 6 in which the tubular valve member contains a plurality of longitudinally offset by-pass ports that are brought into sequential registration with the body portion of the exhaust chamber as the tubular valve member moves toward the second position.

8. The improvement defined in claim 6 in which (a) the tubular valve member is formed with an interior partition which serves as a seat for one end of the spring; and

(b) the metering orifice is defined by an opening extending through the partition.

References Cited by the Examiner UNITED STATES PATENTS M. CARY NELSON, Primary Examiner.

MARTIN P. SCHWADRON, Examiner. 

1. IN A DIRECTIONAL CONTROL VALVE OF THE TYPE INCLUDING A HOUSING CONTAINING A THROUGH VALVE BORE AND A GENERALLY C-SHAPED EXHAUST CHAMBER HAVING A BODY PORTION PARALLEL WITH AND SPACED FROM THE VALVE BORE TO DEFINE AN INTERVENING INTERNAL HOUSING WALL AND TWO LEG PORTIONS WHICH EXTEND IN DIRECTIONS TRANSVERSE TO THE VALVE BORE AND INTERSECT THAT BORE ADJACENT ITS OPPOSITE ENDS, A FIRST PASSAGE EXTENDING THROUGH SAID INTERNAL WALL AND CONNECTING THE VALVE BORE WITH THE BODY PORTION OF THE EXHAUST CHAMBER, AND A SECOND PASSAGE EXTENDING INTO THE HOUSING FROM ITS OUTSIDE SURFACE AND INTERSECTING THE BODY PORTION OF THE EXHAUST CHAMBER IN ALIGNMENT WITH AND ACROSS THE CHAMBER FROM THE FIRST PASSAGE, THE IMPROVEMENT WHICH COMPRISES PRIORITY VALVE MEANS EXTENDING ACROSS THE BODY PORTION OF THE EXHAUST CHAMBER AND HAVING OPPOSITE END PORTIONS THAT ARE RECEIVED IN SAID FIRST AND SECOND PASSAGES, THE PRIORITY VALVE MEANS SERVING TO TRANSMIT TO THE SECOND PASSAGE ALL OF THE FLUID FLOWING THROUGH THE FIRST PASSAGE WHEN THE RATE OF THIS FLOW IS BELOW A PREDETERMINED VALUE AND, WHEN THE RATE OF FLOW IS ABOVE THIS VALUE, TO TRANSMIT FLUID AT SAID PREDETERMINED FLOW RATE TO THE SECOND PASSAGE AND TO DIVERT THE BALANCE OR SAID FLOW INTO THE EXHAUST CHAMBER. 